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Subchapter 7. General Industry Safety Orders
Group 3. General Plant Equipment and Special Operations
Article 14. Marine Terminal Operations

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§3463. Hazardous Atmospheres and Substances.

(a) Carbon Monoxide.

(1) Exposure limits. The carbon monoxide content of the atmosphere in a room, building, vehicle, railcar or any enclosed space shall be maintained at not more than 50 parts per million (0.005%) as an 8-hour time-weighted average and employees shall be removed from the enclosed space if the carbon monoxide concentration exceeds 100 parts per million (0.01%).

(2) Testing. Tests to determine carbon monoxide concentration shall be made when necessary to ensure that employee exposure does not exceed the limits specified in subsection (1).

(3) Instrumentation. Tests for carbon monoxide concentration shall be made by qualified persons using gas detector tube units meeting the requirements of 30 CFR Part 11 or other equivalent methods.

(4) Records. A record of the date, time, location and results of carbon monoxide tests shall be available for at least thirty (30) days.

(b) Pesticides (Fumigants, Insecticides, Hazardous Preservatives).

(1) When the employer is aware that cargo in a space is or has been stowed, handled, or treated with a pesticide (fumigant, insecticide, or hazardous preservative), a determination shall be made as to whether a hazardous atmosphere is present in the space, and only employees protected as required in subsection (5) of this section shall enter the space if it is hazardous.

(2) Tests to determine the atmospheric concentration of chemicals used to treat cargo shall be:

(A) Appropriate for the hazard involved;

(B) Conducted by qualified persons; and

(C) Performed at the intervals necessary to ensure that employee exposure does not exceed the permissible exposure limit for the chemical involved.

(3) Results of any test shall be available for at least thirty (30) days.

(4) Chemicals shall only be applied to cargoes by qualified persons.

(5) Only qualified persons shall enter hazardous atmospheres, in which case the following provisions apply:

(A) Persons entering a space containing a hazardous atmosphere shall be protected by respiratory and emergency protective equipment meeting the requirements of Article 10 and Section 5144 of the General Industry Safety Orders; and

(B) Persons entering a space containing a hazardous atmosphere shall be instructed in the nature of the hazard, precautions to be taken, and the use of protective and emergency equipment. Standby observers, similarly equipped and instructed, shall continuously monitor the activity of employees within such a space.

(6) Signs shall be clearly posted where fumigants, pesticides or hazardous preservatives have created a hazardous atmosphere. These signs shall note the danger, identify specific chemical hazards, and give appropriate information and precautions, including instructions for the emergency treatment of employees affected by any chemical in use.

(c) Asbestos. When the packaging of asbestos cargo leaks, spillage shall be cleaned up by qualified employees protected from the harmful effects of asbestos as required by Section 5208.

(d) Welding, Cutting and Heating on Preservative Coatings.

(1) Before hot work is commenced on surfaces covered by a preservative coating of unknown flammability, a test shall be made by a qualified person to determine the coating's flammability. Preservative coatings shall be considered highly flammable when scrapings burn with extreme rapidity.

(2) Appropriate precaution shall be taken to prevent ignition of highly flammable hardened preservative coatings. Highly flammable coatings shall be stripped from the area to be heated. An uncoiled fire hose with fog nozzle, under pressure, shall be immediately available in the hot work area.

(3) Surfaces covered with preservative coatings shall be stripped for at least 4 inches (10.2 cm) from the area of heat application or employees shall be protected by supplied air respirators.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. New section filed 12-12-84; effective thirtieth day thereafter (Register 84, No. 50). For prior history, see Register 80, No. 27.

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